If I understood your question correctly: You want to change one original layer then all the duplicated layers are changed accordingly, right?
I usually select the layers of a repeating element (like a header, the navigation bar, a footer, or a button...etc.) and convert it into a "smart object". (right click on the selected layers)
When you duplicate the "smart object" layer, Photoshop assures you all the duplicates are just the alias of the original. When you need to update, just double click the thumbnail of the smart object layer. Photoshop would pop up a separate canvas. Make your changes, save and close. Your changes will be applied to all the alias layers.
Smart Object is very useful dealing with repeating elements. It's like the "symbol" in Illustrator and Flash. Smart Object can contain other Smart Objects too.
Btw, a shortcut for duplicating layer style: ("Alt" + Drag) the style effects from the origin layer to the target layer. You can ("alt"+drag) the entire effects, or just one effect, i.e. if you only want to copy the gradient overlay without others.